Abstract 11729: Elevated Procoagulant Platelets Predict Myocardial Infarction or Cardiac Death at 10 Months in Symptomatic Carotid Stenosis

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Background: Symptomatic carotid stenosis is associated with elevated myocardial infarction (MI) risk. Better risk prediction and intervention targets may help reduce adverse cardiac events. Coated-platelets, a subset of procoagulant platelets observed upon dual agonist stimulation with collagen and thrombin, predict stroke recurrence in symptomatic carotid disease, but the association with MI risk is unknown. Here we assess whether coated-platelets predict MI or sudden cardiac death (SCD) in symptomatic carotid stenosis. Methods: Patients with symptomatic ≥50% carotid artery stenosis were enrolled and coated-platelet levels assayed within 92 hours of stroke onset. Demographics, comorbidities and interventions were recorded. MI (4 th universal definition) and SCD (death from MI or arrhythmia) were determined by chart review and confirmed by blinded adjudication. The Area Under the Curve (AUC) was calculated for coated-platelet levels for predicting MI or SCD and the most sensitive and specific cutoff identified using Youdon’s Index. Predictors of MI or SCD were determined by Cox Proportional Hazards analysis. Results: We enrolled 179 patients (mean age 67, 85% male, 43% diabetic, 44% smokers, 45% with coronary disease, 26% with carotid revascularization at discharge). Eleven MI’s (5 fatal) and 4 SCD’s without MI (8.4%) occurred over 10.1±3.6 months. Baseline coated-platelets ≥54.6% were associated with risk of MI or SCD (AUC, 0.687±0.0842, p=0.0265, 53% sensitivity, 85% specificity). Age (HR=1.074, p=0.0187) and the interaction between elevated coated-platelets and carotid revascularization at discharge (HR=37.6, p=0.0182) were retained as significant on multivariate analysis. Conclusions: Our findings revealed a 37.6 increased hazard of MI or SCD among revascularized symptomatic carotid stenosis patients with ≥54.6% coated-platelets. A high rate of often fatal MI was also noted after revascularization, supporting the need to optimize cardiovascular risk management. Our results suggest a role for coated-platelets as biomarkers of perioperative cardiovascular risk and as potential novel treatment targets to reduce perioperative adverse cardiac events in symptomatic carotid stenosis.